1. Field
Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to an apparatus and method of exploiting frequency diversity gain for neighboring cells in a orthogonal frequency-division multiplexing (OFMD) system.
2. Background
Neighboring cell measurements in wireless systems is generally performed based on Reference Pilot (RP) signals. Typically in OFDM systems, the RP signal spans the bandwidth (BW) of the system. However the RP signals are only present at certain symbols and frequency tones with a predetermined periodicity. This not only reduces overhead but also provides time and frequency diversity.
In general, neighboring cell measurements spanning the entire BW in an OFDM system requires vast amounts of memory and significant Fast Fourier Transform (FFT) computation resources. Hence, the neighbor cell measurements are typically limited to a minimum BW. Fox example, in 3GPP LTE systems the min BW is 1.44 Mhz. Consequently, the limitation to minimum BW reduces the frequency diversity gain of the OFMD system and may also bias the comparison of neighbor cell measurements with serving cell, which is measured over the entire BW. This in turn effects idle mode and connected mode handovers (HO) in high frequency selective channels.
Thus, aspects of this invention provide an apparatus and method for improving the frequency diversity gain of neighboring cell measurements while maintaining the same level FFT processing requirements needed for minimum BW measurements.
Appendix A is also attached hereto, and includes additional drawings and description of aspects of the present apparatus and method.